I literally just put all the editor.zip files into a normal folder and added client.cs/description.txt, and there seems to be no problems. This runs the Mission Editor as a client-side Add-On rather than needing special adjustments to the shortcut.
There'll probably be some huge crashes when you try and do certain things but it didn't happen to me so I'm putting this out here.
Yea Yea....Thanx To You My Blockland Broke...AND MY KEY TOO!!!!